The objective of the proposed research is to use the Trichoplusia ni-Chelonus spp. system to develop a basic understanding of arthropod development and how parasites (and man) may manipulate the host now been shown to induce several forms Chelonus parasites have now been shown to induce several forms of redirected development of their insect hosts by mechanisms that had not heretofore been considered or realized as possible. Thus, we seek an understanding of the components of the manipulated pathways and how these are manipulated by the parasite. The specific aims of the proposed research are 1) Identify the specific biochemical components of the female wasp which are responsible for redirected host development, 2) Purify the active factor(s) and 3) Identify of the target site of the factor(s) in the host. The methodology for identifying the components of the wasp which redirect development involved the use of several different approaches, each of which addresses the question from a different direction. The venom material, and viral and non- viral fractions of the calyx fluid, will be separately bioassayed by injection into host eggs. The eggs will be observed for redirected development. Also, antibodies active against each of these three materials will be injected into previously injected or naturally stung eggs so as to inhibit the action of the material. The methodology for the purifying the active factor(s) will involve both classical purification techniques (gradients, column chromatography, electrophoretic procedures, etc.) and the use of affinity columns based on antibodies. The methodology for the identification of the target site will involve injection of purified factor(s) radiolabelled by natural or organic chemistry means to follow their binding to the putative target. Alternatively, photaffinity procedures will also be used. As a third alternative, antibodies will used in immunohistochemical efforts to identify the targets site.